AskDefine | Define oligotrophic

User Contributed Dictionary

English

Adjective

oligotrophic
  1. In the context of "of a diet": being deficient in nutrition
  2. In the context of "of a lake or an ocean etc": being deficient in plant nutrients, such as nitrogen or phosphorus

Related terms

Antonyms

Extensive Definition

An oligotrophic ecosystem or environment is one that offers little to sustain life. The term is commonly utilised to describe bodies of water or soils with very low nutrient levels. It derives etymologically from the Greek oligo (small, little, few) and trophe (nutrients, food).
Oligotrophic environments are of special interest for the alternative energy sources and survival strategies upon which life could rely.

Examples

Antarctic

Lake Vostok, a freshwater lake which has been isolated from the world beneath 4 km of Antarctic ice for approximately 500,000 years is frequently held to be a primary example of an oligotrophic environment.

Australia

The sandplains and lateritic soils of southern Western Australia, where an extremely thick craton has precluded any geological activity since the Cambrian and there has been no glaciation to renew soils since the Carboniferous. Thus, soils are extremely nutrient-poor and most vegetation must use strategies such as proteoid roots to gain even the smallest quantities of such nutrients as phosphorus and sulfur.
The vegetation in these regions, however, is remarkable for its biodiversity, which in places is as great as that of a tropical rainforest and produces some of the most spectacular wildflowers in the world. It is however, severely threatened by climate change which has moved the winter rain belt south, and also by clearing for agriculture through use of fertilizers, which is primarily driven by low land costs that make farming economic even with yield a fraction of those in Europe or North America.

South America

An example of oligotrophic soils are those on white-sands, with soil pH lower than 5.0, on the Rio Negro basin on northern Amazonia that house very low-diversity, extremely fragile forests and savannahs drained by blackwater rivers; dark water colour due to high concentration of tannins, humic acids and other organic compounds derived from the very slow decomposition of plant matter. Similar forests are found in the oligotrophic waters of the Patía River delta on the Pacific side of the Andes.

References

External links

oligotrophic in Esperanto: Malmultvivsubtena
oligotrophic in French: Oligotrophe
oligotrophic in Dutch: Oligotroof
oligotrophic in Norwegian: Oligotrof
oligotrophic in Norwegian Nynorsk: Oligotrofisk
oligotrophic in Finnish: Oligotrofinen
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